Large earth moving or grading equipment commonly has an enclosed cab having a dashboard containing controls and a driver's seat so that the driver may sit while in the driving position. During use of this equipment in hot weather, the driver commonly leaves the door open to allow air to circulate inside the cab to maintain the cab at a comfortable temperature. The driver is often in a standing position inside the cab so that he may see over the dash to perform the duties required of him and observe the field of action during grading or earth moving. As a result, the driver is exposed to the danger of falling out of the cab through the open door.
The prior art shows various assorted apparatuses to bar entry by an individual into hazardous areas. In U.S. Pat. No. 1,207,920 issued to A. Howe there is taught an apparatus that is pivotally connected to a wall and has a single bar member which can be rotated downward to bar passage of an individual into an unsafe area adjacent a passageway.
U.S. Pat. No. 1,405,309 issued to A. E. Matthews, U.S. Pat. No. 2,592,879 issued to L. U. Eyerly and U.S. Pat. No. 2,674,486 issued to S. W. Alderfer show various substantially solid retainer bars to retain a passenger in a vehicle seat during movement. In U.S. Pat. No. 3,282,604 issued to A. G. Goldberg is shown a solid retaining bar which bridges a passenger area and prevents movement laterally on the seat which is provided with means to adjust such restraint to accept a particular seat structure. Further, U.S. Pat. No. 3,737,192 issued to Hirsch teaches the provision of fixed handrails along walking passageways on earth moving equipment to provide handholds for individuals walking on the equipment to steady their walk.
In U.S. Pat. No. 1,596,795 issued to J. T. Blakeney is shown a series of adjustable horizontal bars which attach to the side walls of an automobile to keep children in the back seat passenger area of the automobile. In U.S. Pat. No. 2,793,069 is taught the structure of a pivotal type vehicle cab door having a lock bar which locks the door closed during operation to prevent accidental opening of the door.
The prior art provides many various apparatus to restrain the movement of individuals inside enclosures of moving vehicles, but none are known to the inventors which satisfactorily solve the problem of operators of these vehicles. Operators often have to stand in cabs in order to be able to properly see the terrain in front of the vehicle and often leave the door of the vehicle cab open to allow air circulation within the vehicle. As the operator is standing, seat restraints are unsatisfactory as he must be able to see over the dash to properly operate the equipment. Furthermore, none of the apparatus known in the prior art provides an apparatus to allow the operator to safely stand in the cab during vehicle operation with the door open to allow air circulation.